distance azimuth manual

8/12/2019 Distance Azimuth Manual

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NAME: Distance/Azimuth Tools v. 1.6

Last modified: February 21, 2005

TOPICS: ArcView 3.x, Distance, Bearing, Azimuth, Angle, Point, Line,Polyline, Polygon, Shape, View, Analysis, Tools, Vertices, Shift Shapes, Move Shapes

AUTHOR: Jeff Jenness, GIS Analysis and Application DesignJenness Enterprises3020 N. Schevene Blvd.Flagstaff, AZ 86004

[email protected]

DESCRIPTION: This extension lets you create a new shapefile based on distances and bearings(azimuths) from either an existing shapefile or from an input table.

New Shapes from Existing Shapes: You can create a new shapefile using distances andazimuths from an existing shapefile. You have the option to create your new shapes based oneither a constant distance and azimuth which applies to all features in the shapefile, or to useunique distances and azimuths from each shape based on "Distance" and "Azimuth" fields in theFeature Attribute Table. In either case, the extension copies each shape (they can be points,lines or polygons) to new locations according to the specified distance and azimuth.

New Shapes from Input Table: You can also create a new shapefile using data from an inputtable. You have three options in this case:

1. Your input table records can reflect a series of points, where the distance and azimuthindicate the change in position from one point to the next. Accordingly, the table needs tocontain fields for the "TO" and "FROM" ID values and the "DISTANCE" and "AZIMUTH"from one point to the next. You must specify the X- and Y-coordinates of the origin point.The extension then offers the you the option to calculate a Point shapefile containing allthose coordinates as individual points, a Polyline shapefile containing a series ofindividual line segments that connect the points, a Polyline shapefile containing a single
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record reflecting all those line segments strung together, and/or a Polygon shapefileconnecting the last point back to the first point.

2. You can also use an input table like the one above, but containing multiple shapes. Inthis case, the table must also contain a field specifying the SHAPE ID value, and youmust enter in coordinates for the origin points of each shape in the table.

3. Your input table records can reflect a set of points that are all some specified distanceand bearing from a central Origin point. This case would apply if, for example, a personstood at a central point and measured the distance and azimuth to several featuresaround them, then wanted to map the positions of those features. In this case, the tablemust contain fields reflecting the "ORIGIN ID", the "TO" ID, the "DISTANCE" and the"AZIMUTH" for each record. The extension will give you the option to create a Pointshapefile for each of the surrounding features, a Point shapefile for the Origin points,and/or a Line shapefile for the line segments connecting the points to their respectiveOrigin points.

Please see the detailed operating instructionsfor a more thorough explanation of how to use thisextension.

Average Azimuths of Polylines in Polyl ine Theme: This extension will calculate the averagebearing of all polylines in a polyline theme, determined as the bearing between the starting pointof a polyline and the ending point of that line. These values will be added to either an existingfield or a new field in the attribute table.

This extension also offers three tools in the View ToolBar relating to distances and bearings.

1. Line Length and Azimuth: This tool allows you to draw a graphic line on thedisplay. After you click on the end point of the line, you will see the length, azimuth,starting coordinates and ending coordinates of your line at the bottom of the screen.

2. Graphic Point from Distance and Azimuth: This tool allows you to click anywhereon the screen, enter in a distance and azimuth, and then create a new graphic point at

the new coordinates. The new coordinates will be displayed at the bottom of the screen.

3. Graphic Point from Point Theme: This tool allows you to click on a point in anactive point theme, enter in a distance and azimuth, and then create a new graphic pointat the new coordinates. The new coordinates of the graphic point will be displayed at thebottom of the screen.

REQUIRES: This extension requires either a feature theme (of Points, Lines or Polygons) to bepresent in the view, or alternatively a table to be present in the project which contains fieldsreflecting the FROM and TO point ID values, and the Distance and Bearing from point to point.

Also, this extension uses new dialogs and therefore requires that the file "avdlog.dll" be present inthe ArcView/BIN32 directory (or $AVBIN/avdlog.dll) and that the Dialog Designer extension be

available in the ArcView/ext32 directory, which they almost certainly are if you're running AV3.1or higher. You don't have to load the Dialog Designer; it just has to be available. If you arerunning ArcView 3.0a, you can download the appropriate files for free from ESRI, at:

http://support.esri.com/index.cfm?fa=downloads.patchesServicePacks.viewPatch&PID=25&MetaID=483

Recommended Citation Format: For those who wish to cite this extension, the authorrecommends something similar to:

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Jenness, J. 2005. Distance/Azimuth Tools (dist_az_tools.avx) extension for ArcView 3.x, v. 1.6.Jenness Enterprises. Available at:http://www.jennessent.com/arcview/distance_azimuth.htm.

Please let me know if you cite this extension in a publication ([email protected]). I will updatethe citation list to include any publications that I am told about.

Table of Contents

General Instructions: .................................................................................................................... 4Inst ructions for Creating New Shapefi les: .................................................................................. 4

1a) Option 1: INPUT THEME, where all features are duplicated using a constant Distance and Azimuth.51b) Option 2: INPUT THEME, where each feature is duplicated according to unique Distance and

Azimuth values............................................................................................................................................ 51c) Option 3: Single Shape Input Table: You will see the following dialog box prompting you for inputinformation: ................................................................................................................................................. 71d) Option 4: Multiple Shape Input Table:.................................................................................................10

Entering Origin Coordinates Manually: ....................................................................................................................... 10

Entering Origin Coordinates by Linking to a Table: .................................................................................................... 111e) Option 5: Input Table for Set of Points surrounding Origin Point: .......................................................11

Instructions for Calculating Average Bearings of Polylines: ................................................. 14Inst ructions for the three ToolBar too ls: .................................................................................. 15

Line Length and Azimuth: ..................................................................................................................15Graphic Point from Distance and Azimuth: ........................................................................................15Graphic Point from Point Theme: .......................................................................................................15

Updates: ....................................................................................................................................... 16

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General Instructions:

1) Begin by placing the "dist_az_tools.avx" file into the ArcView extensions directory(../../Av_gis30/Arcview/ext32/).

2) After starting ArcView, load the extension by clicking on File --> Extensions , scrollingdown through the list of available extensions, and then clicking on the checkbox next to theextension called "Distance and Azimuth Tools."

3) Make sure your input themes and/or input tables are present in your project. This extensionlets you select your input data from a list of themes/tables that are currently available in yourproject. It does not let you search the hard drive for your input data.

Instructions for Creating New Shapefiles:

(Instructions for the three ToolBar toolsare located near the end of this document...)

1) From your View buttons, click on the icon. This brings up the Select the Method forCreating New Shapes:dialog box:

Here you have the option to choose which type of input data you have and the method you

want to use for creating your new shapefiles. Each option is explained in detail below, butessentially you can choose between using a Feature Theme (i.e. a Point, Line or Polygon theme)or a Table for your input data. If you use a Feature Theme, this extension will take each Point,Line or Polygon in the theme and copy it to a new location, based on a Distance and Azimuth thatyou provide. You can copy the features using a constant Distance and Azimuth, or you canprovide a separate Distance and Azimuth for each feature.

If you use a Table for your input data, you can either use a table in which each record in thetable represents a single point or vertex in a series of points/vertices, or you can use a table inwhich the records represent a set of points surrounding an origin point.

If your table represents a series of points (3rd

and 4thoptions), you need to provide the X- and

Y-coordinates of the origin point and the extension then calculates the coordinates of all the restof the points based on specified distances and azimuths from one point to the next. Your inputtable must therefore have fields containing ID values for both the current point and the next pointin the series, as well as fields containing Distance and Azimuth values that show where the nextpoint in the series should be.

Your Series input table can also contain data for multiple shapes. If your table contains aSHAPE ID field, then this extension will prompt you for the origin coordinates for each separateshape and then will create separate features for each Shape ID value.

If your table represents a Set of points surrounding an origin point, this extension will promptyou for the X- and Y-coordinates of your origin point (or points), then calculate the position of all

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the points in the table based on their distance and azimuth from the origin. Your input table musttherefore have fields containing ID values for the To points and their respective Origin points,and Distance and the Azimuth values reflecting where the To point is in relation to its originpoint.

IMPORTANT: This extension tries to alert you to incorrect input data using the followingcriteria. First, AZIMUTH values should be in units of Degrees and must always be positive.Negative AZIMUTH values will produce an error message and stop the extension from running.The AZIMUTH value for Due North can be either 0 or 360, and the values increase as you goclockwise (i.e. East = 90, South = 180 and West = 270.). Second, If your AZIMUTH values aregreater than 360, this extension will divide the value by 360 and use the remainder as the

AZIMUTH value (i.e. Modulus 360). In other words, if your AZIMUTH value equals 370, 730 or1,090 degrees, this extension will treat that as being an AZIMUTH equal to 10 degrees.

1a) Option 1: INPUT THEME, where all features are duplicated using a constant Distanceand Azimuth.

You will see the following dialog box prompting you for input information:

This option copies each point, line or polygon in your Input Theme to new locations based ona constant Distance and Azimuth, essentially moving the entire shapefile by a single Distanceand Azimuth. You need to enter in your values for Distance and Azimuth and then pick whichfields you want to include in your new theme. You can pick multiple fields by holding the SHIFTkey down as you select them.

1b) Option 2: INPUT THEME, where each feature is dupli cated according to uniqueDistance and Azimuth values.


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This option copies each point, line or polygon in your Input Theme to new locations based onunique Distance and Azimuth values that are found in DISTANCE and AZIMUTH fields in thetheme's Feature Attribute Table. In this case, each point, line or polygon has it's own Distanceand Azimuth value in the Distance and Azimuth fields, and the extension copies that shape tonew coordinates based on those Distance and Azimuth values. In the illustration on the first pageof this document, the author used a theme of the Continental United States and duplicated eachstate according to a couple of numeric fields, producing a map of scrambled states.

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1c) Option 3: Single Shape Input Table: You will see the following dialog box promptingyou for input information:

Begin by selecting the input table from the list of available tables. After you've selected yourtable, the fields for that table will appear in the four listboxes on the right. Select the fields thatcontain your "FROM", "TO", "DISTANCE" and "AZIMUTH" values.

Each record in the table should essentially reflect a line segment starting at one point andreaching to a new point created by the specified distance and azimuth. The next record in thetable reflects a new line segment starting where the last one ended, and continues to a new pointbased on it's specified distance and azimuth.

This extension sorts the table according to the values in the "FROM" field, and these valuescan be understood as ID values for each vertex in the shape, or as ID values for each point in the

final set of points. All calculations are done in the order of the sorted "FROM" values, so it isimportant to make sure these values are correct. After you've selected your "FROM" field, thisextension will go through all the values in that field and find the lowest value. The extensionassumes this lowest value is your Origin point and prompts you to enter the X- and Y-coordinatesin the text boxes below the list boxes.

This extension assumes that there are no duplicate values in the "FROM" field. If duplicatevalues exist, the extension will not know how to sort them. The extension checks for duplicatevalues before it allows you to exit from this dialog box, and will prompt you with the following alertif it finds a duplicate "FROM" value. If you get this message, the author strongly recommendsyou repair your data before proceeding with your calculations.

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By the way, it is important to know if the values in your "FROM" field are in "String" format or"Numerical" format. The extension will sort the features based on the "FROM" field regardless ofwhether they are Strings or Numbers, but you should be aware that Numbers in String formathave a different sort order than Numbers in Numerical format. Strings are sorted alphabeticallywhile numbers are sorted numerically. The numbers 1 through 21 are sorted in the followingways:

A. Numerical Format:1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21

B. String Format:1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 2, 20, 21, 3, 4, 5, 6, 7, 8, 9

You also need to select a field containing your "TO" values. This field is almost irrelevantbecause it is only used when creating a series of points, and then only to get an ID value for the

last point. This extension does not do any sorting or calculating based on the "TO" values.Regardless of the "TO" value in a record, the extension will calculate coordinates for eachconsecutive point based on the order of the sorted "FROM" values. Your "TO" field should be inthe same format as your "FROM" field (i.e. if one is numerical, then the other should be, too.)

The "DISTANCE" and "AZIMUTH" fields must be numeric. Values in the "DISTANCE" fieldshould be in the map units of whatever coordinate system you are working in. For example, ifyou use a UTM projection, your distance units should be in Meters. Azimuth values should be indecimal degrees. This extension will work properly regardless of whether your view is projectedor not.

After you've entered in your X- and Y-coordinates for your origin point, then select the formatyou want your output to be in. You can choose any or all of the following four shapefile formats.

I. Point Shapefile containing all points in file: This option will give you a Point shapefilewith the following fields in the Attribute Table:

a. Shape: This will contain the actual points in the shapefile.b. "FROM" Field: This will contain the ID Values for each point, taken from the

"FROM" field you selected earlier. The ID of the last point in the theme will betaken from the "TO" field you selected.

c. X_Coord: The X-coordinate of the point.d. Y_Coord: The Y-coordinate of the point.

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II. A Set o f Lines Reflecting Each Line Segment: This option gives you a line shapefile inwhich each line represents the line segment described by each record in your input table.It's made up of a series of line segments that connect to each other. The shapefile includesthe following fields in the Attribute Table:

a. Shape: This will contain the actual line segments, marked as "Polylines".b. Length: This length is drawn from the "Distance" field you selected.

c. Segment_ID: Each line segment is assigned an ID number as it's created. Thisfield contains those numbers.

d. From: This contains the ID value of the beginning of the line segment, and it'sdrawn from the "FROM" field you selected.

e. To: This contains the ID value of the end of the line segment, and it's drawn fromthe "TO" field you selected.

f. Azimuth: This value is drawn from the "Azimuth" field you selected.

III. A Single polyline of combined line segments: This option gives you a single polyline ofall the line segments linked together. The shapefile contains a single feature with thefollowing fields:

a. Length: This represents the total length of the polyline.b. ID: This just gives the polyline an ID value which is useful in many circumstances.

It's ID value will be "1".

IV. A Single polygon, connecting fi rs t and last points: This option gives you a polygoncreated by connecting the last point in the series back to the origin point. The shapefilecontains a single feature with the following fields:

a. Area: This represents the total area enclosed by the polygon.b. ID: This just gives the polygon an ID value which is useful in many circumstances.

It's ID value will be "1".

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1d) Option 4: Multip le Shape Input Table:


This option is very similar to the "Single Shape Input Table"option described above, exceptthat in this case your input table can contain multiple shapes. The input table must have a fieldcontaining ID values for each shape.

The output shapefiles are similar to those in the Single Shape Input Tableabove, except thateach shapefile also includes a SHAPE ID field describing which shape that point, line segment,polyline or polygon is a part of. Also, the Polyline and Polygon shapefiles will contain multiplepolylines or polygons.

The tool needs to know the origin points for each of your new shapes, and you can specifythese origin points by either entering them manually or by linking to a table containing origincoordinates. After you have selected your SHAPE ID field, then the Link To Table buttonbecomes active. After you have selected the fields containing your "SHAPE ID" and "FROM"fields, then the "Enter Coordinates" button becomes active.

Entering Origin Coordinates Manually: You will need to enter X- and Y-coordinates for theorigin points of each of your shapes before you will be able to click the "OK" button. Once youclick the "Enter Coordinates" button, you will see the following dialog prompting you for Origincoordinates for each shape:

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The dialog checks to see how many unique shape ID values you have, then finds the lowest"FROM" value for each shape ID value. You can see these values on the dialog so you can besure you're entering coordinates for the correct point. If you skip any of the SHAPE ID values,then the extension will not create new points, lines or polygons for those SHAPE IDs.

Entering Origin Coordinates by Linking to a Table: If you have a table containing theorigin points of each of your shapes, you can skip entering the coordinates manually. Click onthe Link to Table button to see the following dialog:

First identify the table containing your origin coordinates, then select the fields containing theShape ID, X-Coordinate and Y-Coordinate values. IMPORTANT: The SHAPE ID field in thistable must contain identical ID values to those specified in the SHAPE ID field from the MultipleShape Input Tabledialog (see above). This table should have only a single record for eachunique ID value, containing a single set of X/Y-Coordinates for each shape. Once you have

identified the relevant fields, click OK.

1e) Option 5: Input Table for Set of Points surrounding Origin Point:


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This option is intended for situations in which you know the coordinates of an origin point, andyou know the distance and azimuth from the origin to a set of features nearby, and you want tomap the coordinates of those features. For example, someone wanting to map the coordinates oftrees in forest stand could walk to a point and set a GPS receiver to gather the coordinates of thatpoint. While the GPS is working, that person could use a compass and rangefinder to record thedistance and azimuths to all the trees around them. This extension will convert all those distance

and azimuth values into X- and Y-coordinates for each tree.

Begin by selecting the proper table from the INPUT Table list. When you select a table, thefields from that table will appear in the other four listboxes. You need to select the fields whichreflect the ID values for the Origin points, the ID values for the new points (or TO points), andthe Distance and Azimuth values.

You also need to enter in X- and Y-coordinates for your Origin points. Once youve selectedthe ORIGIN ID field, the Enter Coordinates and Link to Table buttons will become active andallow you to assign coordinates for each origin point (see 1d) Option 4: Multiple Shape InputTable for a description of how these buttons work).

You have three output options.

I. A POINT shapefile containing all points in file: This option gives you a Point shapefilewhere the points reflect the X- and Y-coordinates of all the TO values in your InputTable. The Feature Attribute Table for this shapefile will contain the X- and Y-coordinatevalues for the point, as well as all the other fields in your original Input table.

II. A Set of Lines connecting the points to the Origin: This option gives you a Polylineshapefile where each line represents the straight-line distance between the Origin pointand the TO point. The Feature Attribute Table for this shapefile will contain all the fieldsin your original Input table.

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III. A POINT shapefile or Origin points: This option gives you a Point shapefile containing aseparate point for each unique Origin point. If your Input table contains 200 records, butthey only refer to 4 origin points, then this shapefile will only contain those 4 points. TheFeature Attribute table for this shapefile will contain the Origin point ID values and the X-and Y-coordinates of the points.

2) Specify Hard Drive Locations to save new Shapefiles: After you've clicked the "OK"button, you will be prompted to specify a location on the hard drive to save your new shapefiles.These are standard ArcView Dialog Boxes and should be familiar to most users. These files arepermanent and will not be deleted when ArcView is shut down.

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Instructions for Calculating Average Bearings o f Polylines:

This is a simple function to calculate the average bearing of polylines, defined as the directbearing from the start- to the end-point of a polyline. If you wish to calculate more sophisticatedstatistics on polylines, including decomposing them into a series of segments and vertices, the

author recommends his Path, with Distances and Bearings extension (seehttp://www.jennessent.com/arcview/path.htm).

Click the button to start the process. This button will not be enabled unless there is at least1 polyline theme present in the view.

You will first be prompted to identify the polyline theme to use:

Next identify the field to save the azimuth values in:

If you choose , then you will need to define your field parameters:

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Click OK and the tool will to work. It will notify you when it has finished:

You will need to open the table to see the new values.

Instructions for the three ToolBar tools:

Line Length and Azimuth: This tool allows you draw a line anywhere on your display byclicking at some point and holding the mouse button down as you move the cursor to a newpoint. When you let up on the mouse button, the Bearing (or Azimuth), Length, and Start/EndCoordinates of that line will appear at the bottom of the screen. This message is also saved toyour clipboard.

This function also draws a gray line on your screen where you dragged your cursor. Previousgray lines will disappear as you draw new lines. Hold the [Shift] key down as you draw if you

want the previous lines to stay on the screen.The Graphic Point from Distance and Azimuthand the Graphic Point from Point Theme tools aresimilar in that both allow you to calculate the coordinates of a new point based on the distanceand azimuth from an existing point. They each produce a graphic symbol at the new pointcoordinates, and draw a graphic line connecting the origin point to the new point.

Graphic Point from Distance and Azimuth: This tool allows you to click anywhere on thescreen and a graphic symbol will appear at that point. You will then be prompted to enter aDistance and Azimuth (see illustration below), and the tool will then calculate a new pointaccording to the values you enter. The coordinates for the new point will appear at the bottom ofthe screen, and a graphic symbol will appear at the coordinates of that new point. This messageis also saved to your clipboard.

Graphic Point from Point Theme: This tool calculates a new point based on a distanceand azimuth from an existing point, and requires that you have a Point theme active in your view.When you click on a point from that Point theme, you will be prompted to enter a Distance and

Azimuth (see illustration below), and the tool will then calculate a new point according to thevalues you enter. The coordinates for the new point will appear at the bottom of the screen, anda graphic symbol will appear at the coordinates of that new point. The message is also saved toyour clipboard.

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Updates:

Version 1.2 corrects a bug that occurs when the input bearing is exactly 90 degrees. Previouslythe extension would treat that instance as if the bearing was 45 degrees.

Version 1.3 fixes a "Variable TheEdgeBearing has not been initialized" error that occurs whenusing the Line Length and Azimuth tool. This version also saves the line length and azimuth tothe clipboard, and reports the azimuth in both azimuthal degrees and compass quadrantbearings.

Version 1.4 adds the option to link to a table containing origin coordinates rather than enteringthem individually. This release also corrects a bug in which a feature with no bearing/azimuthvalue would receive the value from the previous feature, and such cases are now summarized ina report at the end of calculation rather than with an alert message each time.

Version 1.4e (Sept. 17, 2003) adds the capability to use themes with Z- and M-attributes and use

String fields for distance / azimuth / origin values.Version 1.5 (Sept. 29, 2004) adds the capability to calculate average bearings of polylines.

Version 1.6 (Feb. 21, 2005) fixes some bugs related to projections and makes some generalchanges.

a) It was not positioning shapes correctly when the view was projected and the user built theshapes from an input table.

b) the Graphic Shape from Distance and Azimuth tool would calculate values based on thegeographic projection even if the view was projected.

c) This version also modifies the Line Length and Azimuth so it erases previous graphicsas you draw them. It will not delete previous graphics if you hold down the shift key asyou draw lines.

d) I cleaned up the initial Analysis Type dialog so that it does not have nearly as much texton it. I also added Help buttons to explain the different options.

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An On-line version of this manual may be viewed at:

http://www.jennessent.com/arcview/distance_azimuth.htm

Enjoy! Please contact the author if you have problems or find bugs.Jeff Jenness [email protected]

3020 N. Schevene Blvd.Flagstaff, AZ 86004USA

Please visit Jenness EnterprisesArcView Extensionssite for more ArcView Extensions and othersoftware by the author. We also offer customized ArcView-based GIS consultationservices tohelp you meet your specific data analysis and application development needs.

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